This invention relates to a diagnostic technique for imaging the shape of a specific blood vessel, e.g., coronary artery, and measuring the blood flow speed in the blood vessel, and also relates to the apparatus used for the treatment of the specific blood vessel.
It is known that the presence of numerous microbubbles in a liquid provides a pronounced imaging effect for the ultrasonic echography. For example, a method disclosed in U.S. Pat. No. 4,265,251 introduces into blood a solid precursor, typically saccharide compound, and numerous microbubbles produced when the saccharide has melted in blood are used for the echography of a selected part of a blood vessel. European patent Laid-open No. 0052575 describes the use of a blood-melted precursor similar to the above-mentioned one, but in the form of particles, each being integrated finer particles so that spaces among finer particles are filled with gas. Another method of U.S. Pat. No. 4,276,885 injects directly into the blood flow numerous microbubbles fixed by gelatin, thereby intensifying the ultrasonic image.